Fix and enable NEW_NON_STRICT_FAST ArgumentsAccess stub on x64.

Fix and enable NEW_NON_STRICT_FAST ArgumentsAccess stub on x64.

R=fschneider@chromium.org
BUG=v8:1903
Committed: http://code.google.com/p/v8/source/detail?r=10411

[fschneider, 2012-01-16 14:25:07]

LGTM.

http://codereview.chromium.org/9179010/diff/1/src/x64/code-stubs-x64.cc
File src/x64/code-stubs-x64.cc (right):

http://codereview.chromium.org/9179010/diff/1/src/x64/code-stubs-x64.cc#newco...
src/x64/code-stubs-x64.cc:2314: //  rsp[16] : receiver displacement
The comment is misleading: This argument is an absolute address, not a
displacement.

http://codereview.chromium.org/9179010/diff/1/src/x64/code-stubs-x64.cc#newco...
src/x64/code-stubs-x64.cc:2454: __ Integer64PlusConstantToSmi(r9, rbx, 0);
Isn't there an instruction to make a smi without adding a constant?

http://codereview.chromium.org/9179010/diff/1/src/x64/code-stubs-x64.cc#newco...
src/x64/code-stubs-x64.cc:2496: // Untag rcx and r8 for the loop below.
Comment should say: Untag rcx for the loop below.

(r8 already untagged)

http://codereview.chromium.org/9179010/diff/1/src/x64/full-codegen-x64.cc
File src/x64/full-codegen-x64.cc (right):

http://codereview.chromium.org/9179010/diff/1/src/x64/full-codegen-x64.cc#new...
src/x64/full-codegen-x64.cc:225: // Arguments to ArgumentsAccessStub and/or
New...:
What's "New..."? I think the comment was fine as it was.

[fschneider, 2012-01-16 14:26:18]

Please make sure that we have test coverage of the different cases in the stub.

On 2012/01/16 14:25:07, fschneider wrote:
> LGTM.
> 
> http://codereview.chromium.org/9179010/diff/1/src/x64/code-stubs-x64.cc
> File src/x64/code-stubs-x64.cc (right):
> 
>
http://codereview.chromium.org/9179010/diff/1/src/x64/code-stubs-x64.cc#newco...
> src/x64/code-stubs-x64.cc:2314: //  rsp[16] : receiver displacement
> The comment is misleading: This argument is an absolute address, not a
> displacement.
> 
>
http://codereview.chromium.org/9179010/diff/1/src/x64/code-stubs-x64.cc#newco...
> src/x64/code-stubs-x64.cc:2454: __ Integer64PlusConstantToSmi(r9, rbx, 0);
> Isn't there an instruction to make a smi without adding a constant?
> 
>
http://codereview.chromium.org/9179010/diff/1/src/x64/code-stubs-x64.cc#newco...
> src/x64/code-stubs-x64.cc:2496: // Untag rcx and r8 for the loop below.
> Comment should say: Untag rcx for the loop below.
> 
> (r8 already untagged)
> 
> http://codereview.chromium.org/9179010/diff/1/src/x64/full-codegen-x64.cc
> File src/x64/full-codegen-x64.cc (right):
> 
>
http://codereview.chromium.org/9179010/diff/1/src/x64/full-codegen-x64.cc#new...
> src/x64/full-codegen-x64.cc:225: // Arguments to ArgumentsAccessStub and/or
> New...:
> What's "New..."? I think the comment was fine as it was.